Chelates and methods of making the same



United States Patent O CHELATES AND METHODS OF MAKING THE SAME Fred W.Hoover and Henry C. Miller, Pembrey, near Wilmington, Del., assignors toE. I. du Pont de Nemours and Company, Wilmington, Del., a corporation ofDelaware No Drawing. Application September 20, 1955 Serial No. 535,520

14 Claims. (Cl. 260-63) This invention relates to the field of chelatecomplexes and their use in the preparation of shaped articles. Moreparticularly, it relates to stable compositions from whichhigh-softening, insoluble polymers can be obtained in useful shapes, andto the process of forming these highsoftening, insoluble polymers.

This application is a continuation-in-part of our copending applicationSerial No. 380,602, filed September 16, 1953, and now abandoned.

Insoluble polymers containing metal chelate groups have been describedpreviously (see, for example, U.S. Patents 2,620,325, 2,634,253, and2,647,106). These polymers are crosslinked through the chelate ringsformed by the union of the multiplicity of chelate-forming groupspresent in the polymer with polyvalent metal atoms. While such polymershave the great advantage of being resistant to heat and solvents, theirtechnical value is severely limited by the fact that it is not possibleto form them into useful articles, e.g., films, sheets, filaments,objects and the like, prior to insolubilization through chelatecrosslinking.

This invention has as an object a method of preparing compositions whichcan be readily converted to crosslinked, insoluble, and infusiblepolymers. A further object comprises such crosslinkable compositions. Astill further object comprises such compositions which are stable, thatis, capable of being stored and handled without gelation or otherdeterioration. Another object is the preparation of stable compositions,including solutions, from which shaped polymer articles can readily beformed, which articles, upon air-drying or moderate baking becometack-free rapidly and are then hard, tough and resistant to light,oxygen, water, acids, alkalies, and the common organic solvents. Stillanother object is the preparation of chelate complexes. Still anotherobject is the provision of esters suitable for polychelation. Otherobjects will appear hereinafter.

These objects are accomplished by the present invention of compositionshaving as their essential ingredients,

(a) An organic compound which is a polyligand, i.e., has in its moleculea plurality, m, of chelating structures, i.e., structures which with apolyvalent metal form a chelate ring, and

'(b) A chelate, with a volatile chelating agent, of a polyvalent metalof absolute valence n, m and n being plural integers and totaling atleast five.

The polyligands suitable for the purpose of this invention are estershaving a plurality, m, of hydroxyl groups esterified with aB-ketomonocarboxylic acid having hydrogen on the u-carbon atom, thealcohol portion of said esters being taken from the class consisting of(1) polyhydric alcohols, and (2) free hydroxyl group-containingpolyhydric alcohol esters of carboxylic acids.

The invention also includes a process of preparing crosslinked organicpolymers, said polymers being insoluble in non-chelating solvents andcontaining metal atoms bonded to the polymer molecules as members ofchelate rings, which comprises forming an intimate mixture of 2,933,475Patented Apr. 19, 1960 (1) an organic compound having in chelatingstructures per molecule, said compound being a polyhydric alcoholB-ketomonocarboxylate as defined above, and (2) a chelate of a volatilechelating agent with a chelateform= ing metal of principal valence n,both In and n being at least two and the sum of m and n being at leastfive; and evaporating the volatile chelating agent and any solventpresent, thereby forming a polymer crosslinked through polyvalent metalchelate groups.

The chemistry of chelate compounds has developed to a remarkable degreein recent years. A good summary of it has been given by H. Diehl in anarticle entitled The Chelate Rings, Chemical Reviews 21, 39-111 (1937).A more extensive and more recent review of the field is presented inChemistry of the Metal Chelate Compounds, by Martell and Calvin(Prentice-Hall, Inc., New York, 1952). See also Gilmans OrganicChemist1yAn Advanced Treatise, John Wiley and Sons, vol. II, the chapterentitled Modern Electronic Concepts of Valence, by J. R. Johnson,particularly at pages 1868- 1883.

A chelating, or chelate-forming, structure is one which contains atleast two donor groups so located with respect to one another that theyare capable of forming a chelate ring with a metal, the chelate ringbeing normally of five or six members. The donor groups are well knownand recognized in chelate chemistry, the principal ones being listed byDiehl (loc. cit., p. 43) and by Martell and Calvin (loc. cit., p. 168).The most important donor groups, and consequently the chelate-formingstructures therefrom, are those which contain oxygen, sulfur, ornitrogen as the donor atoms.

Organic compounds containing chelating structures are called ligands inthe language of chelate chemistry. For the purpose of this invention itis necessary to use organic compounds having at least two ligandfunctions (i.e., two chelating structures) and therefore these compoundsare often referred to herein as polyligands. Simple examples ofpolyligands are monomers or polymers containing a plurality offi-ketoester groups, as defined above. Many examples of such polyligandswill be given in the description which follows.

The second component of the crosslinkabe compositions of this inventionis a chelate of a volatile chelating agent with apolyvalentchelate-forming metal. By volatile chelating agent is meant here anorganic compound containing at least one (and generally only one)chelateforming structure, which compound boils below 300 C. at 760 mm.pressure. A number of such volatile chelating agents are known, such asacetylacetone or ethyl acetoacetate. The chelate-forming metals form awelldefined class. They are identified in the table on p. 182 of theMartell and Calvin book already referred to. For the purpose of thisinvention, it is necessary that the chelate-forming metal be polyvalent,i.e., be in a plural valence state.

The relative proportions of the two active components in the mixtures ofthis invention, that is, of the polyvalent metal chelate of a volatilechelating agent with respect to the polyligand, are not critical.However, it is desirable that there be enough of the metal chelatepresent to react with at least 10%, and preferably at least 25% of thechelating structures of the polyligand. In most cases, the twocomponents are used in approximately equivalent ratio, that is, there isused enough of the metal chelate to react with approximately all of thechelating structures of the polyligand. An excess of the metal chelatecan be used if desired, e.g., up to three times the calculated amount oreven more.

In some cases, the components of the crosslinkable compositions of thisinvention are liquid and compatible with one another, and the resultingcomposition is a homogeneous solution. More often, the components arecompatible but it is recommended or necessary to use suflicient of amutual solvent if a homogeneous composition fluid at room temperature isdesired. For this purpose, any inert, volatile solvent can be used.Preferably, the solution is as concentrated as possible, consistent witha practical viscosity. In still other cases, the compositions are nothomogeneous at room temperature, and even at elevated temperatures,e.g., up to about 100 C. This is the case particularly when thepolyligand is a polymer which is a solid of limited solubility in theusual solvents at room temperature. Whether or not the compositions ofthis invention are homogeneous and/or fluid at room temperature islargely immaterial for the purpose of preparing shaped objects, althoughcompositions which are fluid solutions at room temperature are generallypreferred because of their greater ease of handling.

What takes place in the mixtures when the volatile chelating agent isevaporated is a ligand exchange which is also termed chelate interchangeor transchelation, paralleling the widely used terms ester interchange,amide interchange, transesterification, transamination, etc. The processis an exchange, or transfer, of the metal from the chelating structuresof the volatile chelating agent to those of the non-volatile polyligand.To illustrate, the transchelation between the ethyl acetoacetate chelateof a divalent metal and a polyligand having acetoacetoxy groups, thelatter being chelate-forming, may be represented by the followingequation, where Me represents the metal, Pol. represents the polyligandmolecule to which the chelate-forming structures are attached, and thering arrows represent the coordinate bonds:

ont-o 0-0 cm,

+2 PoL-O-C O-OHr-C 0-011:

Thus, when both the number m of chelate-forming structures perpolyligand molecule and the principal valence n of the metal are atleast two and the sum of m and n is at least five, a chelated polymer isformed and crosslinking through the chelate rings takes place betweenthe polymer molecules. The formation of chelate crosslinkages, that is,of a space network of chelate linkages, derives from the involvement inthe reaction of two polyfunctional reactants, of which at least one ismore than bifunetional.

In the transchelation process of the present invention, evaporation ofthe solvent, if any is present, and of the volatile chelating agent byair-drying or, if desired, moderate baking, leaves a polymer crosslinkedthrough the chelate rings. This polymer contains the metal which waspresent in the chelate of the volatile chelating agent. The polymer isinfusible, and insoluble in the common organic solvents. The onlysolvents which effect it are those having a strong chelating action,since they tend to reverse the equilibrium and to form, partly orcompletely, a soluble chelate of the metal present in the chelate ringsof the polymer.

ess is that the non-volatile polyligand and the polyvalent metal chelateof a volatile chelating agent can be combined in intimate mixtures, suchas homogeneous solutions, without precipitation of the crosslinked,chelated polymer. Thus, these intimate mixtures can be formed, storedand handled at will, and it is only on removal of the volatile materialsby evaporation that formation of the crosslinked polymer takes place.This is because an equilibrium between ligands and metal exists in thecompositions, which is shifted, with formation of the chelatecrosslinked polymer, only when the volatile ligand is removed.

When, as is normally the case, a shaped structure of the chelatecrosslinked polymer is desired, the shaping is done essentiallyconcurrently with the removal of the volatile chelating agent, e.g., bycasting, extruding or pressing objects such as films, sheets, filaments,molded structures and the like, and completing the evaporation of thevolatile materials as needed. In cases where the chelated composition ismoldable at high temperatures, shaping may be accomplished subsequentlyto chelation.

As already mentioned, the intimate mixture of the polymeric polyligandand metal chelate of a volatile chelating agent need not be ahomogeneous solution at room temperature. It is only necessary that itscomponents form a homogeneous system at the temperature at which theshaped object is being formed. It is often desirable to add to themixture a small additional amount of a volatile chelating agent, e.g.,acetylacetone, as insurance against premature gelation of the chelatecrosslinked polymer.

The invention is illustrated in greater details in the examples whichfollow, in which parts are by weight unless otherwise specified. Inthese examples the viscosity measurements were made at room temperature,this being about 25 C.

EXAMPLE I A polyallyl acetoacetate having a degree of polymerization of8-10 (such polymers can be made by ester interchange by the first methodof Example II, below, of a low molecular weight polyallyl alcohol, e.g.,that of US. 2,431,224, with ethyl acetoacetate, or by directpolymerization of monomeric allyl acetoacetate) was mixed withequivalent amounts of various metal ohelates of volatile chelatingagents, as shown in the table below. A small amount of solvent was addedin each case, in order to give solutions having viscosities suitable forthe preparation of coatings. The solutions so prepared were clear andstable towards gelation. Films 1-2 mils thick cast from these solutionswere rapidly converted to insoluble, clear, hard coatings uponair-drying or baking at 120 C. for 30 minutes.

Solutions ojpolyliaand and metal chelatea Parts/ Metal Chelate PartsSolvent Polymer A. Bis (methyl sallcylato)beryl1lum Toluene/ethanol.

B. Tris(metl1yl salieylato)aluminum.. 113 Toluene/1-butanol.

O. Bls(buty1 acetoacetato)copper II.-.-- 133 Do.

D. Tris(acetylacetono)iron III 83 Do.

E. Bis(ethyl acetoaeetato)berylliu 94 Toluene F. Tris (ethylacetoaeetato)aluminum 97 Do The outstanding advantage of this transc elaon p c- 75 the visc s ty inc eased somewhat at first and then re-EXAMPLE H Five hundred parts of a castor oil modified polyglycerylphthalate resin containing, by weight, 55% castor oil, 41.9%polyglyceryl phthalate and 3.1% glycerol, having an acid number of 6.5,a hydroxyl number of 151, and a viscosity in 65% xylene solution at 25C. of 13 poises, was heated with 300 parts of ethyl acetoacetate and 500parts of toluene. In three hours heating there was collected 80 parts byvolume of the toluene/ethanol binary distilling at 77 C. Removal of anadditional 200 parts by volume of toluene left a solution, having aviscosity of 0.14 poise at 40% solids, of the polyacetoacetate of thepolyester resin. This product will be referred to in the remainder ofthis example as the polyligand for the sake of brevity.

Another method of preparing this polyligand consists in using diketeneto introduce acetoacetate groups. Six hundred and fifteen parts of theabove-described 65% xylene solution of the castor oil modifiedpolyglyceryl phthalate resin was diluted with 385 parts of toluene. Tothe mixture was added 2 parts of p-toluenesulfonic acid, then 100 partsof diketene was added at a temperature of 65 C. in two hours and theunchanged diketene was destroyed by addition of absolute alcohol.

The 40% toluene solution of the polyacetoacetate of the polyester resin,described above, or similar toluene solutions of difierentconcentrations, were used as follows:

A. A solution of 5.5 parts of tris(ethyl acetoacetate)- aluminum in 4parts of n-butyl alcohol and 2 parts of ethyl acetoacetate was mixedwith 50' parts of the 40% solution of the polyligand described above.The clear solution obtained had a solids content of 34% and a viscosityof 0.36 poise. The viscosity remained unchanged upon storage at roomtemperature. Films cast from this solution, to give dry films 1-2 milsthick, became tack-free in two hours at room temperature and afterdrying overnight were hard, tough, flexible, insoluble,

. and resistant to water, aqueous alkali and acid. Similar filmproperties were shown by coatings baked for 30 minutes at 400 F. Thesefilms were only slightly discolored on baking. This is in contrast tocoatings prepared from the polyligand containing no metal chelate, whichdid not dry even after prolonged periods at room temperature andremained soft and sticky even after baking at elevated temperatures.

The eifect on the final film properties of variations in thepolyligand/metal chelate ratio is illustrated in the following table,summarizing experiments in which his- (ethyl acetoacetato)aluminum wascombined with the polyligand solution to give an aluminum content in thefinal film varying from to 300% of the amount required to chelate withall the acetoacetoxy groups of the polyligand. Films on bonderized steelwere baked for 30 minutes at 150 C. The coatings were all colorless andglossy.

B. When the above solution of tris(ethyl acetoacetate)- :aluminum wasreplaced by a solution of 5.65 parts of bis- (ethylacetoacetato)magnesium in a mixture of 12 parts of n-butyl alcohol and 1part of ethyl acetoacetate, there was obtained a coating compositioncontaining 25% solids and having a viscosity of 0.32 poise, whichviscosity remained constant upon storage at room temperature. Hard,flexible, inert coatings were obtained from. this mixture uponair-drying or baking.

C. A mixture of 13.4 parts of bis(salicylaldehydo)- nickel II, parts ofa 44.7% solids solution, as described above, of the polyligand and 49parts of p-methoxyethanol gave a stagle, clear solution. Films uponair-drying or baking were clear, hard, palergreen, tough and inert.Similar results were observed and dark green films were obtained whenthe nickel/salicylaldehyde chelate was replaced with 13.7 parts ofbis(salicylaldehydo)- copper II.

D. Tetrakis(acetylacetono)zirconium (12.3 parts) was dissolved in 100parts of a 51% solution, as described above, of the polyligand to givestable solutions. Films cast therefrom could be air-dried or baked toclear, colorless, inert coatings.

E. Diisopropyl bis( ethyl acetoacetato)titanate was prepared by adding51 parts of ethyl acetoacetate to 27.8 parts of tetraisopropyl titanate.Addition of 196 parts of a 51% solution of the polyligand gave a clear,yellow, stable solution which upon air-drying or baking in thin filmsyielded clear, inert, insoluble coatings of excellent hardness andtoughness.

F. One hundred twenty-seven parts of a 51% solution of the polyligand,20.8 parts of bis(ethyl acetoacetate) zinc and 15 parts of ethylacetoacetate gave a similar stable, film-forming solution.

G. One hundred forty-one parts of a 51% solution of the polyligand, 18.2parts of bis(acetylacetono)rnanganese II and 8 parts of n-butyl alcoholgave a stable, film-forming solution. Similar stable, film-formingsolutions were obtained using the aluminum chelates of 3-methyl-, 3-ethyl-, and 3-allyl-2,4-pentanedione, the copper chelate ofethyl(trifluoroaceto)acetate, bis(acetylacetono)zinc, bis (ethylacetoacetato)c0balt II, bis(ethyl acetoacetato)copper II, bis(acetylacetono)magnesi1un, bis(butyl acetoacet ato)copper II,tris(acetylacetono)aluminum, tris(methyl salicylato)alurninum,'bis(methyl salicylato)beryllium, and tris(ethyl acetoacetato)iron III.

EXAMPLE III The procedure of Example II was repeated with a coconut oilmodified polyglyceryl phthalate having the following properties.Composition: 29.7% coconut oil, 60.5% polyglyceryl phthalate, 5.2%triacetin, 4.6% glycerol; acid number 9.1, hydroxyl number 124. Thereaction mixture, which was a solution of the acetoacetate of thispolyester resin in ethyl acetoacetate and toluene, had a viscosity of0.18 poise at 36.4% solids. Twenty-five parts of this solution wastreated with a solution of 2.54 parts of bis-ethylacetoacetato)magnesium in 2.4 parts of n-butyl alcohol and 1.7 parts oftoluene. There resulted a clear, stable solution. Thin films of thissolution deposited on steel became insoluble on air-drying or baking togive hard, mar-resistant coatings.

EXAMPLE IV The ester interchange procedure of Example II was applied toa coconut oil acid modified polypentaerythrityl phthalate having thefollowing properties. Composition: 42.2% polypentaerythrityl phthalate,48.1% pentaerythritol ester of coconut oil fatty acids and 8.9%pentaerythritol; acid number 13.3, hydroxyl number 173, viscosity of1.13 poises at 49.5% solids in toluene. The resulting acetoacetate ofthis polyester resin had a viscosity of 0.40 poise at 56.1% solids in amixture of toluene and ethyl acetoacetate. Into 100 parts of thissolution was dissolved 18.8 parts of tris(ethyl acetoacetato)aluminum togive a clear, stable solution. Thin films of this solution becameinsoluble and hard on air-drying or baking.

7 EXAMPLE v The ester interchange procedure of Example II was applied toa hydrogenated castor oil modified polyglyceryl phthalate having thefollowing properties. Composition: 55% hydrogenated castor oil, 41 .9%polyglyceryl phthalate, 3.1% glycerol; acid number 4.1, viscosity 2.0poises at 55% solids in toluene. The resulting polyester acetoacetatehad a viscosity of 1.19 poises at 55.7% solids in a mixture of tolueneand ethyl acetoacetate. This solution, diluted with 10% by volume ofethyl acetoacetate, was mixed with 27.6% by weight (based on the resinsolids) of tris(ethyl acetoacetato)aluminum, which on stirring andwarming dissolved rapidly to give a clear, stable solution. Films ofthis solution, after air-drying overnight or baking for 30 minutes at 95C., were insoluble, hard, tough and mar-resistant.

EXAMPLE VI The castor oil modified polyglycerol phthalate used inExample II was reacted, using the ester interchange procedure describedin Example II, with 1.5 equivalents (based on the hydroxyl content ofthe polyester) of ethyl trifluoroacetoacetate. Removal of thetoluene/ethanol binary followed by removal of some toluene left asolution of the trifluoroacetoacetate of the polyester resin having aviscosity of 0.005 poise at 30% solids. Three parts of this solution wasmixed with a toluene solution of 0.49 part oftris(3-methyl-2,4-pepntancdiono)-aluminum. This solution gelled, butbecame clear again and completely stable upon addition of a very smallamount of 3-methyl-2,4-pentanedione. Films of this solution deposited onsteel panels and baked at 95 C. for 30 minutes gave clear, hard,flexible coatings unaffected by immersion in boiling water for one hour.Similar results were obtained with tris(acetylacetono)aluminum.

EXAMPLE VII The castor oil modified polyglycerol phthalate of Example IIwas treated with 1.2 equivalents of ethyl benzoylacetate by the esterinterchange procedure of Example II. There was obtained a toluenesolution of the benzoylacetate of the polyester resin which wasconcentrated to 40% solids content. Three and one-half parts of thissolution was treated with a toluene solution of 0.41 part of tris(ethy1acetoacetato)aluminum. The resulting clear solution, when deposited onsteel panels and baked at 95 C. for 30 minutes, gave clear, hard,flexible films which were unchanged when immersed in boiling water for30 minutes. Similar results were obtained usingtris(acetylacetono)aluminum and baking the films at 150 C. for 30minutes.

EXAMPLE VIII A mixture of 200 parts of castor oil, 200 parts of tolueneand 120 parts of ethyl acetoacetate (an excess over the quantitycalculated to react with the ricinoleic acid hydroxyl groups) wasdistilled slowly. There was collected 32 parts of the toluene/ ethanolbinary mixture boiling at 77 C. Evaporation of the remaining solvent andexcess ethyl acetoacetate left 254 parts of a liquid residue having aviscosity of 2.94 poises. This consisted chiefly of thetris-acetoacetate of glycerol tris-ricinoleate.

To 100 parts of the above material was added 30 parts of tris(ethylacetoacetato)aluminum to give a clear, viscous fluid which did not gelon aging at room temperature. This composition was filming-forming.Coatings became tack-free in four hours at room temperature. Uponair-drying overnight, the coatings were set to touch, tough, extensibleand similar in mechanical properties to air-dried films of naturaldrying oils.

A pigmented composition was prepared by grinding 9.4 parts of pigmentgrade titanium dioxide, 14.6 parts of zinc oxide pigment and 18.0 partsof magnesium silicate extender into 30 parts of the tris-acetoacetate ofglyceryl tris-ricinoleate. Two parts of ethyl acetoacetate was added assolvent to assist in the dispersion of the pigment. To the pigmentedcomposition was added 11 parts of tris(ethyl acetoacetato)aluminum. Thefinal composition, after thinning slightly with toluene, could bebrushed readily on wood or other surfaces to give a coating which driedovernight at room temperature and compared favorably in properties withcommercial exterior paints made from linseed oil.

EXAMPLE IX From a mixture of 62.5 parts of pentaerythritol, 240 parts ofethyl acetoacetate and 160 parts of dioxane was distilled 100 parts ofethanol. Evaporation of all volatile materials left 176 parts ofpentaerythrityl tetraacetoacetate as a clear oil having a viscosity of2.63 poises. This oil was compatible with an equal weight of tris(ethylacetoacetato)aluminum to give a viscous mixture which did not gel uponstorage at room temperature. Thin films cast therefrom and air-driedbecame tack-free in minutes to give hard, glossy, colorless coatings.After drying 18 hours, the films were somewhat brittle and resembledthin films of rosin in mechanical properties.

EXAMPLE X One part of the castor oil acetoacetate used in Example VIII,0.65 part of the pentaerythrityl tetraaceto acetate of Example IX and0.96 part of tris(ethyl acetoacetato)aluminum gave a clear, compatible,stable mixture which, in thin films, became tack-free in six hours atroom temperature. After standing overnight, the films were hard, glossy,insoluble in non-cheleating organic solvents and inert to dilute aqueousacids and alkalies and had the hardness and toughness of a conventionalvarnish.

EXAMPLE XI The monoglyceride of castor oil was prepared by heating undernitrogen a mixture of 800 parts of castor oil, 160 parts of glycerol and0.5 part of litharge to a temperature of 200 C. for one hour. Themixture was cooled to C., 1040 parts of ethyl acetoacetate and 910 partsof toluene were added and 780 volumes of toluene/ethanol binary boilingat 77 C. were removed by distillation. Evaporation of the solvent andexcess ethyl acetoacetate left a liquid residue of 1520 parts having aviscosity of 1.83 poises. This product consisted chiefly of the mixedglyceryl ester of acetoacetic acid and of 12-acetoacetoxyoleic acid.

A mixture of 100 parts of this material and 69 parts of tris(ethylacetoacetato)aluminum gave a stable, clear, viscous liquid having aviscosity of 12.5 poises. Thin films cast from this mixture, air-driedor baked at elevated temperatures, gave hard, mar-resistant, glossyfilms which were tough, insoluble in non-chelating solvents and inert todilute acids and alkalies.

EXAMPLE XII The castor oil-modified polyglyceryl phthalate of Example IIwas reacted, using the ester interchange procedure of that example, with1.0 equivalent (based on the hydroxyl content of the polyester) of2-carbethoxycyclopentanone,

EXAMPLE XIII An oil-free, hydroxyl containing alkyd resin of acid number10 and hydroxyl number 106 was prepared by reacting one mole each ofglycerin and decamethylene glycol with two moles of phthalic anhydrideat 150-200 C. for 15 hours. The ot-acetylacetoacetate of this polyesterwas prepared by the ester interchange procedure of Example II with 1.0equivalent (based on the hydroxyl content of the polyester) of ethyla-acetylacetoacetate CO-OHs Removal of the toluene/ethanol binaryfollowed by concentration gave a solution having a viscosity of 0.27poise at 48% solids. Fifteen parts of this solution mixed with 1.1 partsof tris(acetylacetono)aluminum gave a composition which gelled onwarming but could be stabilized by addition of a small amount ofacetylacetone. Films from this solution cast on steel plates and bakedat 150 C. for 30 minutes gave colorless, hard coatings having excellentimpact flexibility.

EXAMPLE XIV p-Vinylbenzyl acetoacetate,

B.P. 125-131 C. at 0.2 mm. pressure, was prepared by ester exchange inrefluxing toluene between ethyl acetoacetate and p-vinylbenzyl alcoholin the presence of hy- 'droquinone.

A methyl acrylate/p-vinylbenzyl acetoacetate copolymer was prepared byrefluxing for six hours a mixture of 45 parts of p-vinylbenzylacetoacetate, 160 parts of methyl acrylate, 750 parts of benzene and 2parts of azobis(isobutyronitrile). Upon precipitation with methanolthere was obtained an 80% yield of the copolymer, having a viscosity of2.75 poises at 47.7% solids in methyl isobutyl ketone. This copolymercontained 79% methyl acrylate as determined by carbon and hydrogenanalysis.

Seventeen parts of the 47.7 copolymer solution in methyl isobutylketone, when mixed with 1.4 parts of tris(ethyl acetoacetato)aluminum,gave a composition which gelled on standing but could be stabilizedagainst gelation by addition of 2 to 3 parts of ethyl acetoacetate.Films from this solution deposited on steel panels and baked at 150 C.for 30 minutes gave hard, colorless coatings having very good solventresistance.

Similar results were obtained using, as the polyligand, a 77/23 (byweight) copolymer of methyl methacrylate and p-vinylbenzyl acetoacetate.

EXAMPLE XV 2-cyanoally1 acetoacetate,

CHa=CGHa-OC OCHr-C O- CH! B.P. 116-117 C. at 1.5 mm. pressure, wasprepared by ester exchange in refluxing toluene between 2-cyanoallylalcohol and excess ethyl acetoacetate in the presence of hydroquinone.

A methyl acrylate/Z-cyanoallyl acetoacetate copolymer was prepared in88% yield by heating for six hours at 75 C. a mixture of parts of2-cyanoallyl acetoacetate, 20 parts of methyl acrylate, 35 parts ofbenzene and 0.25 parts of azobis(isobutyronitrile). The copolymer,precipitated with methanol, contained 2.13% nitrogen, corresponding to21.8% by weight of Z-cyanoallyl acetoacetate. Films cast from a toluenesolution of this copolymer containing an equivalent mole per chelatinggroup of the polyligand) amount of tris-ethyl acetoi6 acetato)aluminumgave, on baking at 150 C. for 30 minutes, hard, flexible, insolublecoatings.

EXAMPLE XVI A solution of 70.3 parts of hexamethylene glycol and partsof diethyl acetonedicarboxylate in toluene was slowly distilled untilabout 75 parts of ethanol/toluene binary, boiling at 78 C., had beencollected. This ester exchange reaction served to form polyhexamethyleneacetonedicarboxylate,

The residue in the still was then concentrated to a solids content of69%, this solution having a viscosity of 5.89 poises. When this solutionof polyligand was mixed with tris(ethyl acetoacetato)alurninum in anamount sufficient to give 65% by weight of the latter, based on polymersolids, and with 60 parts of ethyl acetacetate, a stable solution wasobtained which gave films that became hard and insoluble on air-dryingor baking. Similar results were obtained when the hexamethylene glycolwas replaced by an equivalent weight of bis(2-hydroxyethyl)-terephthalate or bis(6-hydroxyhexyl)-adipate.

EXAMPLE XVII A copolymer of vinyl acetate and allyl acetoacetate wasprepared by heating a mixture of 19.2 parts of vinyl acetate, 14.2 partsof allyl acetoacetate, 1.03 parts of azobis(isobutyronitrile) and 34.4parts of benzene for 19 hours at 75 C. in a nitrogen atmosphere. Theresulting; solution had a viscosity of 0.6 poise and a solids content.of 45.7%, indicating a conversion to polymer of 94.3%.. The copolymerhad a vinyl acetate/allyl acetoacetate mo-- lar ratio of about 2.5/1.

Upon addition of 0.36 part of tris(ethyl acetoacetato)-- aluminum to 3parts of this polymer solution, a clear' solution was obtained, fromwhich films were cast on: phosphated steel and baked for 30 minutes atC.. to give very hard coatings insoluble in toluene.

EXAMPLE 'XVIII Copolymers of vinyl chloride with three polymerizable:materials having chelating structures, viz., allyl aceto-- acetate,methallyl acetoacetate, and allyl benzoylacetate,. were prepared asfollows: Glass pressure bottles were charged with 3 parts ofazobis(isobutyronitrile), 150 parts; of benzene, 15 parts of tert.-butylalcohol, and monomers in the amounts shown in the following table. Thebottles were flushed with nitrogen, capped, and agitated at 60 C. for 19hours. The contents were then poured into methanol, the polymer whichseparated was washed with methanol and then dried in a vacuum over undernitrogen. Polymer yields, solution viscosities (poises/ percent solidsin methyl isobutyl ketone), percent chlorine by analysis, and percentvinyl chloride by weight are shown in the table below.

Solutions of these copolymers, after treatment with an equivalent weightof tn's(ethyl acetoacetato)aluminum, gave films which became insolubleupon air-drying or baking. Films cast from the same solutions to whiclnno aluminum chelate had been added remained soluble upon air-drying orbaking.

11 EXAMPLE XIX A polymer containing a number of acetoacetate groups wasprepared as follows: Partial hydrolysis of an ethylene/vinyl acetatecopolymer (25 mole percent vinyl acetate) was effected by adding asolution of 4 parts of potassium hydroxide in 160 parts of isopropylalcohol to 67.2 parts of the copolymer in 430 parts of toluene. Afterheating the mixture at reflux for two hours the resulting solution wassteamed to separate the hydrolyzed polymer, which had a saponificationequivalent of 202, indicating 22% hydrolysis. Fifty parts of thishydrolyzed copolymer was esterified by heating with 10 parts of ethylacetoacetate in toluene, removing the ethanol formed as a tolueneazeotrope. The theoretical quantity of ethanol was removed during 20hours at reflux, and the resulting solution was concentrated to 224parts to increase its viscosity for casting purposes.

An aliquot portion of the above polyligand solution was combined withone equivalent of tris(ethyl acetoacetato)aluminum and a small amount ofethyl acetoacetate, and cast on a glass plate. After warming the filmslowly to 125 C., removing volatile materials under reduced pressure,and stripping the film from the plate there was obtained a clearself-supporting film with slight surface tackiness. This film had atensile strength of 3880 lbs/sq. in., a break elongation of 560% and aninitial modulus of 515. When held at 50% elongation for one minute, itretracted essentially completely when released, indicating considerableresilience (88% work recovery). In comparison, the initial unchelatedpolymer is a tacky gum having no elastic properties.

Similarly resilient thin sheets were prepared by substituting copper andzinc chelates for the aluminum chelate of this example, or bysubstituting the benzoyl acetoacetic ester of a hydrolyzedethylene/vinyl acetate copolymer for the acetoacetic ester.

EXAMPLE XX A mixture of 4.68 parts of cellulose acetate (49% combinedacetic acid), 65 parts of ethyl acetoacetate and 5 parts of toluene washeated to reflux for 22 hours, removing the ethanol as it formed. Theresidue was concentrated to 55 parts to give a solution of good castingviscosity containing the cellulose acetate/acetoacetate.

An aliquot portion of this polyligand solution was mixed with oneequivalent (calculated on the acetoacetate groups) of tris(ethylacetoacetato)aluminum and cast on a glass plate. The solvent was removedby warming to 125 C. and the volatile chelating agent was removed underreduced pressure. On stripping the film from the plate there wasobtained a clear, stiff self-supporting film, which did not melt at 300C.

EXAMPLE XXI A copolymer of vinyl acetate (9% by weight) and vinylchloride (91% by weight) was partially hydrolyzed to a productcontaining, in addition to the vinyl chloride, 2.3% by weight ofhydroxyl groups and 3% by weight of vinyl acetate. A polymericpolyligand was prepared from this copolymer by heating it with ethylacetoacetate in a cyclohexanone/toluene mixture and removing the ethanolas it formed. After 23 hours refluxing the residue was concentrated tocasting viscosity, mixed with an equivalent quantity of tris(ethylacetoacetato)aluminum and cast on a glass plate. After removal of thesolvent, the monomeric ligand was removed under reduced pressure at 100C. and the film was removed from the plate, producing a clear, stiffsheet insoluble in a cyclohexanone/toluene mixture and retaining itsstrength up to about 250 C., whereas an otherwise similar but unchelatedcontrol lost its strength at 75 C.

Specific additional examples of polyligands as already defined includesethyleneglycoldibenzoyl acetate, glycerol triacetoacetate, thep-ketoacylates of hydroxyacid esters of polyhydric alcohols, etc.Another type of polyligand comprises polymer materials of high molecularweight (addition or condensation polymers) having at least two, butgenerally a larger number, of chelating structures. These include, forexample, the esters of hydroxyl-containing polymers such as polyvinylalcohol, hydrolyzed ethylene/vinyl acetate polymers, cellulose,cellulose esters, cellulose ethers, polyester resins having freehydroxyl groups and the like with acyclic or or cyclic fi-ketoacids suchas acetoacetic acids or 2-carboxycyclopentanone or B-diketoacids such asu-benzoylacetoacetic acid, u-acetylacetoacetic acid or 4-carboxy-5,5-dimethylcyclohexane-1,3-dione; the polymers and copolymers offl-ketoesters of p-vinylbenzyl alcohol or 2- cyanoallyl alcohol;polyester resins from glycols such as hexamethylene glycol ordecamethylene glycol and chelate-forming dicarboxylic acids such asacetone dicarboxylic acid; and the like.

Two types of polyligands are of particular utility. One of these is thatof the fi-ketoacylates of hydroxymonocarboxylic acid esters of monomericand polymeric polyhydric alcohols.

In the examples above this phase of the invention has been illustratedin connection with the acetoacetates of partial or complete ricinoleicacid esters of glycerol. However, this phase of the invention includesbroadly the esters, with any fl-ketomonocarboxylic acid having at leastone hydrogen atom attached to the carbon atom between the keto andcarboxyl groups, of any partial or complete ester of a polyhydricalcohol with an aliphatic hydroxymonocarboxylic acid. Thus, the newproducts of this invention include, for example, the acetoacetates,trichloroacetoacetates, trifluoroacetoacetates, propionacetates,butyroacetates, caproacetates, a-acetopropionates,'y-ethoxyacetoacetates, a-acetophenylacetates, benzoylacetates,2-furoylacetates, 2-thenoylacetates, a-benzoylpropionates, u-benzoylacetoacetates, and a-acetylacetoacetates of the partial or completehydroxyacetates of ethylene glycol, dodecamethylene glycol, cellulose,hydrolyzed ethylene/vinyl acetate copolymers, polyallyl alcohol, etc.;B-hydroxypropionates of propylene glycol, glycerol, etc.; lactates ofhexamethylene glycol, mannitol, polyvinyl alcohol, etc.;a-hydroxybutyrates of pentaerythritol, sorbitol, etc.;10-hydroxystearates of erythritol, glycerol, etc.; 9-hydroxystearates ofethylene glycol, glycerol, etc.; glycerate of ethylene glycol;9,10-dihydroxystearate of glycerol; a-hydroxyvinyl acetate of ethyleneglycol; and the like.

As already stated, there should be at least two p-ketomonoacyloxy groupspresent in each molecule of the esters of this type. These groups havethe general formula R -COCHR --COO--, wherein R is an organic radicalstable under the reaction conditions. For reasons of availability of thecompounds, R is preferably a hydrocarbon group, but it can also be ahydrocarbon group containing essentially unreactive substituents such asnon-labile halogen, preferably chlorine or fluorine, acyclic or cyclicether oxygen or thioether sulfur, or the like. Still more preferably, Ris a hydrocarbon group of one to six carbon atoms free from aliphaticunsaturation. The radical R is preferably hydrogen but can be ahydrocarbon group, preferably of one to six carbon atoms and free fromaliphatic unsaturation. Since the principal use of the fi-ketoacylhydroxyacid esters is to act as ligands in the subsequent formation ofmetal chelates, the most available tl-ketomonoacyloxy group, i.e., theacetoacetoxy group, is the preferred one.

The preferred aliphatic hydroxyacid esters are those derived frompolyhydric alcohols having from 2 to 6 hydroxy groups, these beingnon-tertiary, i.e., primary or secondary, i.e., attached tohydrogen-bearing carbon, and of from 2 to 6 carbon atoms, and fromaliphatic monohydroxymonocarboxylic acids free from functional groupsother than the hydroxy and carboxyl groups.

St ll more preferably, the monohydroxymonocarboxylic acid is one havmgfrom 2 to 18 carbon atoms and havmg at most one carbon-to-carbonunsaturation, and that ethylemc. The most useful esters are those ofglycerol with the abovedefined hydroxyacids. Mixtures of hydroxyacidesters, or mixed hydroxyacid esters of a single polyhydric alcohol, canbe used.

Another preferred class of polyligands for use in the compositions ofthis invention is that of polyester resins having free hydroxyl groupsfurther plurally esterified with a B-ketomonocarboxylic acid having atleast one hydrogen atom attached to the carbon atom between the carboxyland keto groups. These new polyligands include, for example, theacetoacetates, trichloroacetoacetates, trifluoroacetoacetates,propionoacetates, butyroacetates, caproacetates, a-acetopropionates,'y-ethoxyacetoacetates, a-acetophenylacetates, benzoylacetates, 2.-furoylacetates, 2-thenoylacetates, a-benzoylpropionates,a-benzoylacetoacetates, and a-acetylacetoacetates of organicsolvent-soluble polyester resins, e.g., the condensation products,having free hydroxyl groups, of glycerol and phthalic acid; glycerol andadipic acid; glycerol and tricarballylic acid; sorbitol and sebacicacid; pentaerythritol and succinic acid; ethylene glycol and adipicacid; mannitol and terephthalic acid; polyvinyl alcohol and glutaricacid; polyallyl alcohol and phthalic acid; hydrolyzed ethylene/vinylacetate copolymers and adipic acid; and the like.

These new polyligands contain, as already indicated at least two,B-ketomonoacyloxy groups in each molecule. These groups have thegeneral formula in which R is an organic radical stable under thereaction conditions. For reasons of availability, R is preferably ahydrocarbon group but it can also be a hydrocarbon group containingessentially unreactive substituents such as non-labile halogen,preferably fluorine or chlorine, acyclic or cyclic ether oxygen orthioether sulfur, or the like. Still more preferably, R is a hydrocarbongroup of 1 to 6 carbon atoms free from aliphatic unsaturation. Theradical R is preferably hydrogen but can be a hydrocarbon'group,preferably of 1 to 6 carbon atoms and free from aliphatic unsaturation.Since the principal use of the modified polyesters is to act as ligandsin the subsequent formation of metal chelates, the most availableB-ketomonoacyloxy group, i.e., the acetoacetoxy group is the preferredone.

The preferred polyesters are the condensation products of polyhydricalcohols having from 2 to 6 hydroxy groups, these being non-tertiary,i.e., primary or secondary, and 2 to 6 carbon atoms, and still morepreferably such alcohols having at least 3 hydroxyl groups and 3 carbonatoms, with dicarboxylic acids free from aliphatic unsaturation, havingno functional groups other than the carboxyl groups, i.e.,unsubstituted, and preferably having from 4 to carbon atoms.Specifically preferred are the polyglyceryl phthalates and thepolypentaerythrityl phthalates. These polyester resins can be modifiedwith monobasic acid esters of polyhydric alcohols such as castor oil orcoconut oil, or with the corresponding monobasic acid themselves such asthe drying or non-drying oil fatty acids, e.g., coconut oil acids orlinseed oil acids.

In order to attain greater flexibility and toughness in films, fibers,etc., from compositions of the present invention, it is preferred thatthey contain in substantial quantity carbon chains of at least eightcarbons in length. This can be attained by the use of long chain acids,e.g., oil acids, by the use of long carbon chain polyhydric alcoholesters and by the use of long carbon chain polymers, these embodimentsbeing illustrated in many of the examples.

The above examples have furnished numerous illustrations of the secondactive component of the crosslinkable compositions of this invention,namely, the polyvalent metal chelate of a volatile chelating agent.

The volatile chelating agents employed in the preparatron of thepolyvalent chelate of the volatile ligand are those most available andmost economical, which are the 1,3-diketones, the fi-ketoesters and thearomatic o-hydroxy aldehydes and esters. Specifically preferred chelatmgagents are acetylacetone, 3-methyl-2,4-pentanedione,3-ethyl-2,4-pentanedione, propionylaceto-ne, trifluoroacetylacetone,2-furoylacetone, Z-thenoylacetone, ethyl acetoacetate, butylacetoacetate, salicylaldehyde, methyl salicylate, and the like. Themetal chelated with these agents can be any of the large number ofpolyvalent metals known to form chelates readily (Martell and Calvin,loc. cit., p. 182). Preferred specific examples are aluminum, becauseits chelates are colorless and readily compatible with most polyligands;cobalt and nickel, because of the particularly good durability of filmscontaining them; zinc, magnesium, zirconium and beryllium, because theyform colorless products; and titanium, copper, manganese and iron, wherecolored products are not objectionable. Still other useful polyvalentmetals include chromium, cadmium, boron, tin, scandium, vanadium, andbismuth. Where colored clears containing specular pigments such as mica,pearl essence, or aluminum are desired, the copper, iron, cobalt,nickel, manganese, or titanium chelates may be employed. Thechelate-forming metals vary somewhat with respect to the ease with whichthey undergo chelate exchange, or transchelation. Although most metalsundergo chelate exchange rapidly, certain metals, of which chromium IIIand cobalt III are examples, are more sluggish. Longer periods ofairdrying higher baking temperatures or even the addition of traces ofstrong acids or other chelate exchange catalysts are sometimes desirablewhen working with the more sluggish metals.

Specific examples of suitable metal chelates of volatile ligands includetris(ethyl acetoacetato)aluminum; bis- (ethyl acetoacetato)zinc;bis(acetylacetono)zinc; bis- (ethyl acetoacetato) cobalt II; bis(ethylacetoacetato)copper II; bis(salicylaldehydo)copper II;bis(acetylacetono)- magnesium; bis(butyl acetoacetato)copper II;tetrakis- (acetylacetono)zirconium; tris(acetylacetono) aluminum;tris(methyl salicylato) aluminum; bis(methyl salicylato)- beryllium;bis(ethyl acetoacetato)magnesiurn; diisopropyl bis(ethylacetoacetato)titanate IV; bis(acetylacetono) manganese II; tris(ethylacetoacetato)iron III; tris(acetylacetono)iron III; tris(ethylbenzoylacetato)aluminum; bis(1,l,1-trifluoro-3-benzoylacetono)copper II;tris[(2- furoyl) acetono] aluminum; and the like.

The crosslinkable compositions of this invention vary in appearance,depending upon the nature of the two active constituents, fromhomogeneous solutions fluid at room temperature to heterogeneous,semi-solid mixtures. In many cases they need not contain any additionalsolvent, although in general, particularly when the polyligand ispolymeric and a fluid solution of convenient viscosity is desired, theuse of an additional solvent is recommended. The solvent can be anyvolatile liquid which is substantially inert towards the two componentsof the solution. In some cases, water can be used, but in generalorganic solvents are preferred, for example, aromatic hydrocarbons,e.g., benzene, toluene or xylene, aliphatic alcohols, e.g., methanol,ethanol, n-butanol, ethers, e.g., di-n-butyl ether, dioxane or the like.These organic solvents need not be anhydrous. The examples illustrate anumber of suitable solvents. The quantity of the solvent is, of course,not critical. It need only be suflicient to decrease the viscosity ofthe solution at shaping temperature to a level practical for the formingof articles such as films, filaments, sheets or molded objects.

The compositions of this invention, regardless of whether they are fluidsolutions or not, are in general stable towards hardening or loss ofplasticity and can 15 be stored for long periods of time. If sometendency to precipitation or gelation is noted on mixing the reactants,such tendency can be overcome by adding a slight excess of the volatilechelating agent to keep the chelated polymer in solution.

One of the most important uses of the compositions of the presentinvention is in the formation of films, either as coatings on substratessuch as metals or as self-supporting films or thin sheets. Film castfrom these compositions becometack-free rapidly upon airdrying, and evenmore rapidly upon baking, for example, at temperatures of 50 to 200 C.for 15 minutes to two hours. These films consist of polymer moleculescrosslinked through the chelate rings formed by the polyvalent metal andthe chelating structures of thepolyligand. The fihns are hard, tough andinert to long exposures (1200 hours or more) in an apparatus designed toprovide an accelerated weathering test. In general, the polyligandsalone without the chelate-forming metal are viscous, non-film-formingliquids which cannot be exposed to such a treatment. The chelated filmsare at least equal to conventional drying oil modified alkyd films indurability. The films are also resistant to water, soap solutions,aqueous acids, aqueous alkalies and the common organic solvents.However, they may be softened or even dissolved by chelating solventssuch as acetylacetone or ethyl acetoacetate.

The setting of these chelated polymers does not depend on the action ofoxygen on unsaturated linkages, as it does with ordinary drying oils.Accordingly, coatings of these polymers are especially inert toward theoxidative degradation reactions which lead to ultimate failure ofair-reactive film formers based on unsaturated oils.

This invention provides a method of forming, handling and storingpolymers which are normally intraactable because of their high softeningpoints and of their insolubility in the common solvents. It is entirelyunexpected and surprising that metal-containing, crosslinked polymerscan be formed and kept as stable compositions, including solutions,which c'ompositions can be converted at any desired time to varioususeful shaped articles of crosslinked polymer.

The chelated polymers obtainable from the compositions of this inventionare outstandingly-useful as protective and decorative coatings for metalsurfaces, e.g., refrigerators, auto bodies, furniture, and the like, andalso for other surfaces such as Wood, glass, porcelain or plastics. Theyare also useful as ingredients of impregnating and coating compositionsfor natural or synthetic fibers and fabrics. Such coating compositionsmay contain, if desired, various modifying agents, e.g., pigments, dyes,plasticizers, extenders, and the like.

The chelated polymers are also useful in the form of self-supportingfilms and thin sheets. Specific uses include wrapping materials for foodproducts, electrical tape, insulating materials for use at relativelyhigh temperatures, flexible materials for use in articles such as bags,hat covers and overshoes. The polymers are further useful in themanufacture by molding or extruding of shaped objects such as tumblers,tableware, chips, tubes, novelty articles, and they can be extruded asfilaments, for use for example in making stretchable fabrics in view oftheir elastic properties. In some cases, articles such as films orfilaments made of these chelate crosslinked polymers exhibit valuableelastic properties.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom. The invention is not limited to the exact details shown anddescribed for obvious modifications will occur to those skilled in theart.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A solution fluid at room temperature comprising as its essentialingredients, (a) an ester having a plurality, m, of hydroxyl groupsesterified with a p-ketomonocarboxylic acid having hydrogen on thea-carbon atom, the alcohol portion of said ester being taken'from theclass consisting of 1) polyhydric alcohols, and (2) free hydroxylgroup-containing polyhydric alcohol esters of carboxylic acids, and (b)a polyvalent metal chelate of a volatile chelating agent boiling below300 C. at 760 mm. pressure and selected from the group consisting of1,3-diketones, fi-ketoesters, and aromatic o-hydroxyaldehydes andesters, said metal having an absolute valence n, both m and n beingplural integers and totaling at least 5, the amount of (b) beingsufficient to react with at least 10% of the chelating structures of(a).

2. The process of preparing films of organic polymers, insoluble innon-chelating solvents which comprises forming into a film, a solutionfluid at room temperature of (a) an ester having a plurality, m, ofhydroxyl groups esterified with a fi-ketomonocarboxylic acid havinghydrogen on the u-carbon atom, the alcohol portion of said ester beingtaken from the class consisting of (l) polyhydric alcohols, and (2) freehydroxyl group-containing polyhydric alcohol esters ofcarboxylic acids,and (b) a polyvalent metal chelate of a volatile chelating agent boilingbelow 300 C. at 760 mm. pressure and selected from the group consistingof 1,3-diketones, fi-ketoesters, and aromatic o-hydroxyaldehydes andesters, said metal having an absolute valence n, both m and n beingplural integers and totaling at least 5, and evaporating the chelatingagent boilingbelow 300 C. and any solvent present from said film. I v

3. The process of preparing-organic polymers insoluble in non-chelatingsolvents which comprises mixing an ester having a plurality, m, ofhydroxyl groups esterified with a p-ketomonocarboxylic acid havinghydrogen on the a-carbon atom, the alcohol portion of said ester beingtaken from the class consisting of (1) polyhydric alcohols, and (2) freehydroxyl group-containing polyhydric alcohol esters of carboxylic acids,with a polyvalent metal chelate of a volatile chelating agent boilingbelow 300 C. at 760 mm. pressure and selected from the group consistingof 1,3-diketones, p-ketoesters, and aromatic o-hydroxy'aldehydes andesters, said metal having an absolute valence n, both m and n beingplural integers and totaling at least 5, and evaporating the chelatingagent boiling below 300 C.

4. The process of preparing films of organic polymers insoluble innon-chelating solvents which comprises forming into a film an intimatemixture of (a) an ester having a plurality, m, of hydroxyl groupsesterified with a p-ketomonocarboxylic acid having hydrogen on the acarbon atom, the alcohol portion of said ester being taken from theclass consisting of (l) polyhydric alcohols, and (2) free hydroxylgroup-containing polyhydric alcohol esters of carboxylic acids, and (b).a polyvalent metal chelate of a volatile chelating agent boiling below300 C. at 760 mm. pressure and selected from the group consisting of1,3-diketones, fi-ketoesters, and aromatic o-hydroxyaldehydes andesters, said metal having an absolute valence n, both m and n beingplural integers and totaling at least 5, and evaporating the chelatingagent.

5. A composition comprising in intimate admixture and as its essentialingredients, (a) an ester having a plurality, m, of hydroxyl groupsesterified with a fl-ketomonocarboxylic acid having hydrogen on thea-carbon atom, the alcohol portion of said ester being taken from theclass consisting of (1) polyhydric alcohols, and (2) free hydroxylgroup-containing polyhydric alcohol esters of carboxylic acids, and (b)a polyvalent metal chelate of a volatile chelating agent boiling below300 C. at 760 mm. pressure and selected from the group consisting of1,3-diketones, p-ketoesters, and aromatic o-hydroxyaldehydes and esters,said metal having an absolute valence n, m and n being plural integersand totaling at least 5,

17 the amount of (b) being sufficient to react with at least 10% of thechelating structures of (a).

6. The solution of claim 8 wherein ingredient (b) is a fi-ketoesterboiling below 300 C. at 760 mm. pressure.

7. The solution of claim 11 wherein ingredient (b) is a 1,3-diketoneboiling below 300 C. at 760 pressure.

8. A solution fluid at room temperature containing (a) a polyhydricalcohol ester of a carboxylic acid, said ester having a plurality, m, ofhydroxyl groups further esterified with a fl-ketomonocarboxylic acidhaving hydrogen on the alpha carbon, and

(b) a polyvalent metal chelate of a volatile chelating agent boilingbelow 300 C. at 760 mm. pressure and selected from the group consistingof 1,3-diketones, fiketoesters, and aromatic o-hydroxyaldehydes andesters, said metal having an absolute valence n,

(a) a polyhydric alcohol ester of a hydroxymonocarboxylic acid, saidester having a plurality, m, of hydroxyl groups esterified with afi-ketomonocarboxylic acid having hydrogen on the alpha carbon, and

the amount of (b) being sufficient to react with at least 10% of theacetoacetoxy structures of (a).

13. A polyvalent metal chelate of a polymeric polyhydricalcohol-polycarboxylic acid condensation product modified by furtheresterification of a plurality, m, of hydroxyl groups thereof with aB-ketomonocarboxylic acid having hydrogen on the alpha carbon, thepolyvalent metal having an absolute valence it, both m and n beingplural integers and totalling at leastfive, said polymer beingcross-linked through said polyvalent metal present in six-memberedchelate rings formed on different polymer chains, said metal being acommon member of said chelate rings, each of said rings having an atomof the polyvalent metal linked to both the carbonylic and carboxylicoxygen atoms of a single B-ketoacyloxy unit.

14. A polymer which is a polyvalent metal chelate of a polyhydricalcohol ester of a hydroxymonocarboxylic acid, which ester has aplurality, m, of free hydroxyl groups esterified with afi-ketomonocarboxylic acid having hydrogen on the alpha carbon, thepolyvalent metal having an absolute valence n, both m and n being pluralintegers and totalling at least five, said polymer being cross-linkedthrough said polyvalent metal present in sixmembered chelate ringsformed on difierent polymer chains, said metal being a common member ofsaid chelatedrings, each of said rings having an atom of the polyvalentmetal linked to both the carbonylic and carboxylic (b) a polyvalentmetal chelate of a volatile chelating agent boiling below 300 C. at 760mm. pressure and selected from the group consisting-of 1,3-diketones,ketoesters, and aromatic o-hydroxy'ald'ehydes and esters, said metalhaving an absolute valence n,

both m and n being plural integers and totalling at least five, theamount of (b) being suflicient to react with at least 10% of theB-ketoacyloxy structures of (a).

11. The solution of claim 10 wherein component (a) is a glycerylricinoleate having a plurality, m, of hydroxyl 40 groups esterified witha fl-ketomonocarboxylic acid having hydrogen on the alpha carbon.

12. A solution fluid at room temperature containing (a) a polyglycerylphthalate with a plurality of hydroxyl groups further esterified withacetoacetic acid, and

.(b) tris(ethy1acetoacetato) aluminum oxygen atoms of a singlefl-ketoacyloxy unit.

References Cited in the file of this patent UNITED STATES PATENTS1,864,909 Jaeger June 28, 1932 1,878,112 Cooper et a1. Sept. 20, 19322,615,860 Burgess Oct, 28, 1952 2,659,711 Wilkins et al. Nov. 17, 19532,665,285 Burgess Jan. 5, 1954 2,693,484 .Cummings et a1. Nov. 2, 1954FOREIGN PATENTS 582,899 Great Britain Dec. 2, 1946 582.900 Great BritainDec. 2, 1946 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2333,4175 April 19 v 1960 Fred W. Hoover et al.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 2 line 43, for "crosslinkabe" read cro'sslinkable column 6, line10, f or "stagle" read stable column 7, line 28, for "pepntanediono)-a'lumi-" read pentanedionodalumiline 66, for "filming-forming" readfilm-forming column 8, line 32, for "non-cheleating" read nonchelating'column 9 line 70 for parts" read part column 10, line 18, for"acetacetate" read acetoacetate line 23, for "bis(6hydroxyhexyl)adipate" read bis(6hydroxyhexyl)adipate line 53, for "over" read ovencolumn 12, line 9, after "acyclic" strike out 'or"; line 71, for"hydroxy" read hydroxyl column l5, line 9, for "Film" read Films line35, for "intraact-" read intract- Signed and sealed this 27th day ofSeptember 1960.

(SEAL) Attest: v

KARL AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents

1. A SOLUTION FLUID AT ROOM TEMPERATURE, COMPRISING AS ITS ESSENTIALINGREDIENTS, (A) AN ESTER HAVING A PLURALITY, M, OF HYDROXYL GROUPSESTERIFIED WITH A B-KETOMONOCARBOXYLIC ACID HAVING HYDROGEN ON THEA-CARBON ATOM, THE ALCOHOL PORTION OF SAID ESTER BEING TAKEN FROM THECLASS CONSISTING OF (1) POLYHYDRIC ALCOHOLS, AND (2) FREE HYDROXYLGROUP-CONTAINING POLYHYDRIC ALCOHOL ESTERS OF CARBOXYLIC ACIDS, AND (B)A POLYVALENT METAL CHELATE OF A VOLATILE CHELATING AGENT BOILING BELOW300*C. AT 760 MM. PRESSURE AND SELECTED FROM THE GROUP CONSISTING OF1,3-DIKETONES, B-KETOESTERS, AND AROMATIC O-HYDROXYALDEHYDES AND ESTERS,SAID METAL HAVING AN ABSOLUTE VALENCE N, BOTH M AND N BEING PLURALINTEGERS AND TOTALING AT LEAST 5, THE AMOUNT OF (B) BEING SUFFICIENT TOREACT WITH AT LEAST 10% OF THE CHELATING STRUCTURES OF (A).